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https://www.readbyqxmd.com/read/29783155/construction-of-hierarchically-porous-monoliths-from-covalent-organic-frameworks-cofs-and-their-application-for-bisphenol-a-removal
#1
Zhongshan Liu, Hongwei Wang, Junjie Ou, Lianfang Chen, Mingliang Ye
Subject to synthetic conditions, covalent organic frameworks (COFs) are usually in powder form. Herein, taking an azine-linked COF as an example, detailed characterizations indicated that accessible aldehyde groups and hydrazine groups (CNNH2 , 88 μmol g-1 ) concurrently existed on its surface. Intrigued by such feature, we have developed an approach based on ring-opening polymerization to shape COF powder into monoliths. The crystallinity and micropore of COF in monoliths were well remained, meanwhile, the ring-opening polymerization remarkably generated macropores ranging from 0...
May 11, 2018: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/29783152/functionalized-graphene-oxides-for-drug-loading-release-and-delivery-of-poorly-water-soluble-anticancer-drug-a-comparative-study
#2
Neha Karki, Himani Tiwari, Mintu Pal, Alok Chaurasia, Rajaram Bal, Penny Joshi, Nanda Gopal Sahoo
In this work, the modification of graphene oxides (GOs) have been done with hydrophilic and biodegradable polymer, polyvinylpyrrolidone (PVP) and other excipient β -cyclodextrin (β-CD) through covalent functionalization for efficient loading and compatible release of sparingly water soluble aromatic anticancer drug SN-38 (7-ethyl-10-hydroxy camptothecin). The drug was loaded onto both GO-PVP and GO-β-CD through the π-π interactions.The release of drug from both the nanocarriers were analyzed in different pH medium of pH 7 (water, neutral medium), pH 5 (acidic buffer) and pH 12 (basic buffer)...
May 18, 2018: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/29783099/leveraging-the-cruzain-s3-subsite-to-increase-affinity-for-reversible-covalent-inhibitors
#3
Lorenzo Cianni, Geraldo Sartori, Fabiana Rosini, Daniela De Vita, Gabriel Pires, Bianca Rebelo Lopes, Andrei Leitão, Antonio C B Burtoloso, Carlos A Montanari
Cruzain is the major cysteine protease of Trypanosoma cruzi, the etiological agent of Chagas disease. Reversible covalent cruzain inhibitors can block the steps of cell differentiation in the parasite and kill the organism. To this end, the description of how inhibitors modified at the P2/P3 positions lead to analogs with greater cruzain affinity to the S2/S3 subsites is of fundamental importance. Albeit many efforts are being employed in the characterization of the interaction processes with S2 subsite, little is known about the cruzain S3 subsite...
April 26, 2018: Bioorganic Chemistry
https://www.readbyqxmd.com/read/29782701/tgf-%C3%AE-1-modified-hyaluronic-acid-poly-glycidol-hydrogels-for-chondrogenic-differentiation-of-human-mesenchymal-stromal-cells
#4
Thomas Böck, Verena Schill, Martin Krähnke, Andre F Steinert, Jörg Tessmar, Torsten Blunk, Jürgen Groll
In cartilage regeneration, the biomimetic functionalization of hydrogels with growth factors is a promising approach to improve the in vivo performance and furthermore the clinical potential of these materials. In order to achieve this without compromising network properties, multifunctional linear poly(glycidol) acrylate (PG-Acr) is synthesized and utilized as crosslinker for hydrogel formation with thiol-functionalized hyaluronic acid via Michael-type addition. As proof-of-principle for a bioactivation, transforming growth factor-beta 1 (TGF-β1) is covalently bound to PG-Acr via Traut's reagent which does not compromise the hydrogel gelation and swelling behavior...
May 21, 2018: Macromolecular Bioscience
https://www.readbyqxmd.com/read/29782155/a-narrow-gap-semiconducting-germanium-allotrope-from-the-oxidation-of-a-layered-zintl-phase-in-ionic-liquids
#5
Zhongjia Tang, Alexander P Litvinchuk, Melissa Gooch, Arnold M Guloy
A metastable germanium allotrope, Ge(oP32), was synthe-sized as polycrystalline powders and single crystals from the mild-oxidation/delithiation of Li7Ge12 in ionic liquids. Its crystal structure, from single crystal X-ray diffraction (P bcm, a = 8.1527(4) Å, b = 11.7572(5) Å, c = 7.7617(4) Å), features a complex covalent network of 4-bonded Ge, resulting from a well-ordered topotactic oxidative condensation of [Ge12 ]7- layers. It is a diamagnetic semiconductor (Eg = 0.33 eV), and transforms exothermically and irreversibly to α-Ge at 363 °C...
May 21, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29782144/the-nitro-group-as-a-masked-electrophile-in-covalent-enzyme-inhibition
#6
Sneha Ray, Dale F Kreitler, Andrew M Gulick, Andrew S Murkin
We report the unprecedented reaction between a nitroalkane and an active-site cysteine residue to yield a thiohydroximate adduct. Structural and kinetic evidence suggests the nitro group is activated by conversion to its nitronic acid tautomer within the active site. The nitro group, therefore, shows promise as a masked electrophile in the design of covalent inhibitors targeting binding pockets with appropriately placed cysteine and general acid residues.
May 21, 2018: ACS Chemical Biology
https://www.readbyqxmd.com/read/29782143/anti-tumor-humoral-and-t-cell-responses-by-mucin-1-conjugates-of-bacteriophage-qb-in-wildtype-mice
#7
Zhaojun Yin, Xuanjun Wu, Katarzyna Kaczanowska, Suttipun Sungsuwan, Marta Comellas-Aragones, Christian Pett, Jin Yu, Claire Baniel, Ulrika Westerlind, M G Finn, Xuefei Huang
Mucin-1 (MUC1) is one of the top ranked tumor associated antigens. In order to generate effective anti-MUC1 immune responses as potential anti-cancer vaccines, MUC1 peptides and glycopeptides have been covalently conjugated to bacteriophage Qb. Immunization of mice with these constructs led to highly potent antibody responses with IgG titers over one million, which are among the highest anti-MUC1 IgG titers reported to date. Furthermore, the high IgG antibody levels persisted for more than six months. The constructs also elicited MUC1 specific cytotoxic T cells, which can selectively kill MUC1 positive tumor cells...
May 21, 2018: ACS Chemical Biology
https://www.readbyqxmd.com/read/29781371/quantification-of-tantalum-sedimentation-rates-in-liquid-embolic-agents
#8
J R Mason, C Dodge, G Benndorf
Background Endovascular treatment (EVT) of brain arteriovenous malformations has evolved from cyanoacrylate derivatives such as N-butyl cyanoacrylate, an adhesive glue, to ethylene vinyl copolymer-based liquid embolics such as Onyx® and SQUID® dissolved in dimethyl sulfoxide. Although these agents offer several advantages, their rapidly decreasing radiopacity, as a result of the sedimentation of tantalum powder, compromises visual control during EVT. This study aims to quantify and compare tantalum sedimentation rates of several liquid embolic agents, and determine their effects on radiopacity...
January 1, 2018: Interventional Neuroradiology
https://www.readbyqxmd.com/read/29781332/a-novel-phenolic-propanediamine-moiety-based-lung-targeting-therapy-for-asthma
#9
Jianbo Li, Yang Yang, Didi Wan, Youmei Peng, Jinjie Zhang
Asthma is one of the most prevalent chronic inflammatory diseases of lung. Current asthma therapy using inhaled corticosteroid often results in undesired treatment outcome due to poor compliance and drugs' lack of tissue specificity. N,N,N'-trimethyl-N'-(2-hydroxyl-3-methyl-5-123 Iiodobenzyl)-1,3-propanediamine (HIPD), a phenolic propanediamine derivative, has been used as an imaging agent for localized pulmonary diseases. Inspired by this, N,N,N'-trimethyl-N'-(4-hydroxyl-benzyl)-1,3-propanediamine (TPD), a new HIPD analog, was proposed as a lung-targeting ligand and covalently conjugated to an anti-inflammatory compound Rhein for asthma therapy...
November 2018: Drug Delivery
https://www.readbyqxmd.com/read/29781019/complex-strain-induced-structural-changes-observed-in-fibrin-assembled-in-human-plasma
#10
G Portale, J Torbet
The structure of the core scaffold of blood clots, the interlinked 3-dimensional network of fibrin fibers, is modified by mechanical forces generated by platelet driven clot retraction, wound repair and shear stress through blood flow. Here X-ray diffraction is used to investigate how uniaxial strain, ε (ε = extension/original length), alters fiber structure in highly aligned human plasma clots covalently cross-linked by Factor XIIIa. Three stretch sensitive axially repeating structures are identified. Firstly, the foundation structure with an initial ≈22 nm axial repeat stretches, fades then disappears at ε ≈ 0...
May 21, 2018: Nanoscale
https://www.readbyqxmd.com/read/29781013/design-and-synthesis-of-aza-indolyl-maleimide-based-covalent-inhibitors-of-glycogen-synthase-kinase-3%C3%AE
#11
Zhimin Yang, Hui Liu, Botao Pan, Fengli He, Zhengying Pan
As an important kinase in multiple signal transduction pathways, GSK-3β has been an attractive target for chemical probe discovery and drug development. Compared to numerous reversible inhibitors that have been developed, covalent inhibitors of GSK-3β are noticeably lacking. Here, we report the discovery of a series of covalent GSK-3β inhibitors by optimizing both non-covalent interactions and reactive groups. Among these covalent inhibitors, compound 38b with a mild α-fluoromethyl amide reactive group emerges as a selective and covalent inhibitor against GSK-3β, effectively inhibits the phosphorylation of glycogen synthase and tau protein, and increases β-catenin's levels in living cells...
May 21, 2018: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/29781007/inorganic-janus-nanosheets-bearing-two-types-of-covalently-bound-organophosphonate-groups-via-regioselective-surface-modification-of-k-4-nb-6-o-17-%C3%A2-3h-2-o
#12
Ryoko Suzuki, Mitsuhito Sudo, Megumi Hirano, Naokazu Idota, Masashi Kunitake, Taisei Nishimi, Yoshiyuki Sugahara
Janus nanosheets were prepared from K4Nb6O17·3H2O by modifying surfaces of their two distinct interlayers in a regioselective and sequential manner and subsequent exfoliation. The surface properties of nanosheets were investigated by phase atomic force microscopy imaging and two types of surfaces were discriminated, indicating that Janus nanosheets were successfully prepared.
May 21, 2018: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/29780993/ideal-reversible-polymer-networks
#13
German Alberto Parada, Xuanhe Zhao
In this article we introduce the concept of ideal reversible polymer networks, which have well-controlled polymer network structures similar to ideal covalent polymer networks but exhibit viscoelastic behaviors due to the presence of reversible crosslinks. We first present a theory to describe the mechanical properties of ideal reversible polymer networks. Because short polymer chains of equal length are used to construct the network, there are no chain entanglements and the chains' Rouse relaxation time is much shorter than the reversible crosslinks' characteristic time...
May 21, 2018: Soft Matter
https://www.readbyqxmd.com/read/29780564/an-iridium-iii-iv-v-redox-series-featuring-a-terminal-imido-complex-with-triplet-ground-state
#14
Markus Kinauer, Martin Diefenbach, Heiko Bamberger, Serhiy Demeshko, Edward J Reijerse, Christian Volkmann, Christian Würtele, Joris van Slageren, Bas de Bruin, Max C Holthausen, Sven Schneider
The iridium(iii/iv/v) imido redox series [Ir(N t Bu){N(CHCHP t Bu2 )2 }]0/+/2+ was synthesized and examined spectroscopically, magnetically, crystallographically and computationally. The monocationic iridium(iv) imide exhibits an electronic doublet ground state with considerable 'imidyl' character as a result of covalent Ir-N t Bu bonding. Reduction gives the neutral imide [Ir(N t Bu){N(CHCHP t Bu2 )2 }] as the first example of an iridium complex with a triplet ground state. Its reactivity with respect to nitrene transfer to selected electrophiles (CO2 ) and nucleophiles (PMe3 ), respectively, is reported...
May 14, 2018: Chemical Science
https://www.readbyqxmd.com/read/29780559/spatially-resolved-acyl-transfer-on-surface-by-organo-catalytic-scanning-probe-nanolithography-o-cspl
#15
Julien Botton, Katharina Gratzer, Cyril François, Vincent Mesquita, Lionel Patrone, Teodor S Balaban, Sylvain Clair, Jean-Luc Parrain, Olivier Chuzel
Groundbreaking research done in the area of nanolithography makes it a versatile tool to produce nanopatterns for a broad range of chemical surface functionalization or physical modifications. We report for the first time an organocatalytic scanning probe nanolithography (o-cSPL) approach. Covalent binding of an organocatalyst on the apex of an atomic force microscope (AFM) tip gives way to a system that allows the formation of locally defined acylated-alcohol patterns on self-assembled monolayers (SAMs). With resolutions comparable to those of other cSPL methods, this first example of o-cSPL holds promise for future applications of bottom-up nanolithography set-ups employing this novel technique...
May 14, 2018: Chemical Science
https://www.readbyqxmd.com/read/29780548/reversible-dispersion-and-release-of-carbon-nanotubes-via-cooperative-clamping-interactions-with-hydrogen-bonded-nanorings
#16
Raquel Chamorro, Leire de Juan-Fernández, Belén Nieto-Ortega, Maria J Mayoral, Santiago Casado, Luisa Ruiz-González, Emilio M Pérez, David González-Rodríguez
Due to their outstanding electronic and mechanical properties, single-walled carbon nanotubes (SWCNTs) are promising nanomaterials for the future generation of optoelectronic devices and composites. However, their scarce solubility limits their application in many technologies that demand solution-processing of high-purity SWCNT samples. Although some non-covalent functionalization approaches have demonstrated their utility in extracting SWCNTs into different media, many of them produce short-lived dispersions or ultimately suffer from contamination by the dispersing agent...
May 7, 2018: Chemical Science
https://www.readbyqxmd.com/read/29780526/covalent-triazine-framework-modified-with-coordinatively-unsaturated-co-or-ni-atoms-for-co-2-electrochemical-reduction
#17
Panpan Su, Kazuyuki Iwase, Takashi Harada, Kazuhide Kamiya, Shuji Nakanishi
The electrochemical reduction of carbon dioxide (CO2 ) has attracted considerable attention as a means of maintaining the carbon cycle. This process still suffers from poor performance, including low faradaic efficiencies and high overpotential. Herein, we attempted to use coordination number as a control parameter to improve the electrocatalytic performance of metal species that have previously been thought to have no CO2 reduction activity. Covalent triazine frameworks (CTF) modified with coordinatively-unsaturated 3d metal atoms (Co, Ni or Cu) were developed for efficient electroreduction of CO2 ...
April 28, 2018: Chemical Science
https://www.readbyqxmd.com/read/29780492/developing-the-structure-property-relationship-to-design-solid-state-multi-stimuli-responsive-materials-and-their-potential-applications-in-different-fields
#18
Bibhisan Roy, Mallu Chenna Reddy, Partha Hazra
Prediction of multi-stimuli responsive behavior in newly developed luminogens is an appealing yet challenging puzzle, since no concrete design strategy has been developed so far. In this article, we demonstrate a potent strategy to gain a deep understanding of the structure-property relationship to design multi-stimuli responsive mechanochromic materials. To achieve our goal, a variety of new isoindolinone core based charge transfer luminogens exhibiting aggregation-induced emission (AIE) have been prepared through C-H bond activation using a cost-effective ruthenium (Ru) metal catalyzed one-pot synthetic strategy...
April 14, 2018: Chemical Science
https://www.readbyqxmd.com/read/29780484/exploiting-the-interactions-between-the-ruthenium-hoveyda-grubbs-catalyst-and-al-modified-mesoporous-silica-the-case-of-sba15-vs-kcc-1
#19
Baraa Werghi, Eva Pump, Mykyta Tretiakov, Edy Abou-Hamad, Andrei Gurinov, Pradeep Doggali, Dalaver H Anjum, Luigi Cavallo, Anissa Bendjeriou-Sedjerari, Jean-Marie Basset
Immobilization of the 2nd generation Hoveyda-Grubbs catalyst HG-II onto well-ordered 2D hexagonal (SBA15) and 3D fibrous (KCC-1) mesostructured silica, which contained tetra-coordinated Al, has been investigated through the Surface Organometallic Chemistry (SOMC) methodology. The main interest of this study lies in the peculiarity of the silica supports, which display a well-defined tetrahedral aluminum hydride site displaying a strong Lewis acid character, [( 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 11111111111111111 11111111111111111 00000000000000000 00000000000000000 00000000000000000 00000000000000000 11111111111111111 11111111111111111 00000000000000000 00000000000000000 00000000000000000 00000000000000000 11111111111111111 11111111111111111 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 Si-O-Si 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 11111111111111111 11111111111111111 00000000000000000 00000000000000000 00000000000000000 00000000000000000 11111111111111111 11111111111111111 00000000000000000 00000000000000000 00000000000000000 00000000000000000 11111111111111111 11111111111111111 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 )( 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 11111111111111111 11111111111111111 00000000000000000 00000000000000000 00000000000000000 00000000000000000 11111111111111111 11111111111111111 00000000000000000 00000000000000000 00000000000000000 00000000000000000 11111111111111111 11111111111111111 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 00000000000000000 Si-O-)2 Al-H]...
April 14, 2018: Chemical Science
https://www.readbyqxmd.com/read/29780435/photoelectrocatalytic-synthesis-of-hydrogen-peroxide-by-molecular-copper-porphyrin-supported-on-titanium-dioxide-nanotubes
#20
Dogukan H Apaydin, Hathaichanok Seelajaroen, Orathip Pengsakul, Patchanita Thamyongkit, Niyazi Serdar Sariciftci, Julia Kunze-Liebhäuser, Engelbert Portenkirchner
We report on a self-assembled system comprising a molecular copper-porphyrin photoelectrocatalyst, 5-(4-carboxy-phenyl)-10,15,20-triphenylporphyrinatocopper(II) (CuTPP-COOH), covalently bound to self-organized, anodic titania nanotube arrays (TiO2 NTs) for photoelectrochemical reduction of oxygen. Visible light irradiation of the porphyrin-covered TiO2 NTs under cathodic polarization up to -0.3 V vs. Normal hydrogen electrode (NHE) photocatalytically produces H2 O2 in pH neutral electrolyte, at room temperature and without need of sacrificial electron donors...
April 24, 2018: ChemCatChem
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